This proposal is for the continuation of the current project: Atomic scale studies of physical-chemical properties of metallic materials for energy applications (NAISS 2023/5-459). This project includes the following main research topics: 1) A large effort is being put in the modelling of physical-chemical properties of copper as a containment barrier for the Swedish repository for spent nuclear fuel: the study of reactions with water and sulfide and hydrogenation of the surfaces and of bulk copper; studies of the structure of grain boundaries in bulk copper and of the distribution of impurities. Impurity accumulation at defects and effects in materials performance. These studies are essential for the safety assessment of the Swedish repository for spent nuclear fuel. This work will continue into this project. 2) Modelling the diffusion of volatile fission products in accident tolerant nuclear reactor fuel for usage in generation IV reactors. The study consists of modelling UN, including relevant defects and studying the distribution and diffusion of fission products in the fuel matrix. The data is essential for understanding fundamental mechanisms and for the validation of experimental methods of determination of diffusion constants which in turn are important parameters for the authorities to evaluate the safety of the fuel. 3) Modelling the capture of different forms of radioactive iodine in connection with accidental releases of radioactivity with diverse origins. The work consists of using cellulose based materials for enhancing iodine capture methods. Iodine is one of the most concerning radioisotopes regarding effects in the health and the environment upon releases. This work is aimed at studying atomic scale mechanisms of the interactions between iodine and absorption/capture materials. The data will be used to improve the iodine capture materials and capture strategies. 4) The relative stability of carbides and nitrides of actinide elements is studied in the context of the development of the fuels for generation IV reactors. Studies of their surfaces will be conducted in 2024. 5) Semiconductor catalysts for light driven catalysis: photocatalysis. The surfaces and structural properties of these materials will be studied for harvesting light and driving chemical reactions that can be used to convert water and biomass molecules to solar fuels and hydrogen. These studies involve accurate investigations of the structures, of the energies and chemical bonding in the systems using quantum mechanical modelling at the density functional theory (DFT) level. To have realistic data these investigations have to make use of periodic, large supercells to account for defects and other low symmetry structural features of the systems. These investigations will study the mechanisms and physical-chemical properties of these important materials. The results will be employed by other scientists that study their performance and further develop systems where these materials operate. The project NAISS 2023/5-459 has generated important data that resulted in several important published reports and manuscripts in preparation (please see the project report). The project was absolutely essential for the granting of two SSM projects that started in September/October 2024.